It has never been the darling of the fish counter, but is cheaper than cod and a guilt-free, environmentally-friendly option in plentiful supply off the British coast. Today, one of the UK's largest fish retailers is launching an image makeover for unfashionable pollack amid mounting concerns about dwindling stocks of over-fished cod.

Pollack, once deemed fit only for the cat, is being given a new name by the supermarket chain Sainsbury's after research showed that many customers were embarrassed to ask for it. Consumers are to be urged to try "colin and chips" on Fridays in preference to their usual haddock and chips. The new name (pronounced co-lan) is French for pollack when cooked, and reflects France's love affair with the British product.

The latest rebranding exercise follows that of the humble pilchard, which was rechristened the Cornish sardine by the local industry in an effort to regenerate the region's faltering economy. The campaign transformed an unfashionable tinned meal-of-last-resort into a popular national favourite.

Alison Austin, environment manager at Sainsbury's, said it was time to make pollack more appealing to British shoppers: "At Sainsbury's we're passionate about sustainable sourcing and protecting dwindling fish stocks. We want to help highlight that there are species to eat other than cod and haddock, which are just as tasty and often cheaper. Many people have said that they can't even tell the difference in taste between cod or pollack, so we urge everyone to try 'colin and chips' on a Friday."

Austin said that if Britons bought as much UK-sourced pollack as the French did, it could make a big difference in saving cod.

The chain's internal research showed that shoppers interested in pollack were embarrassed to have to ask for it by name. Celebrity chefs have lent their support to the fish, saying its relatively bland taste makes it versatile in recipes.

Sainsbury's is one of the largest fish retailers in the UK, selling £400m worth of fish every year from chiller cabinets and fresh fish counters. Fresh Sainsbury's pollack can be bought in-store all year-round (pre-packed) priced at £9.90 per kilo.

It claims to sell more pollack than any other supermarket and, after appointing a panel of experts to give the fish a complete makeover, has created Jackson Pollock-inspired packaging by the designer Wayne Hemingway. The limited edition packaging will be trialled in 10 UK stores today.